Atomically dispersed WO3-x species on nickel enable efficient alkaline hydrogen oxidation reaction via optimizing adsorption of *H and *OH intermediates

Although nickel-based catalysts are promising alternatives to platinum-group metals for the alkaline hydrogen oxidation reaction (HOR), their performance is limited by the inappropriate hydrogen and hydroxyl binding energy and unfavorable interfacial water molecules. Traditional nickel-based heterostructures have been proposed with great promise to address some of the above issues. Nevertheless, their performance still lags significantly behind that of precious metal catalysts, constrained by limited active sites and the poor conductivity of metal oxides. Herein, we address these challenges through constructing a novel heterointerface, where atomically dispersed WO 3-x species are anchored on Ni nanoparticles (Ni-W 1 O 3-x /C) to achieve higher metal atom utilization and expose more active sites. Operando studies demonstrate that WO 3-x species play critical roles in mitigating competitive hydrogen and hydroxyl adsorption on Ni by serving as hydroxyl adsorption sites, and in optimizing the interfacial water structure for promoted OH - diffusion. These synergistic effects collectively contribute to the superior HOR activity of Ni-W 1 O 3-x /C catalyst. Remarkably, the anion exchange membrane fuel cells employing the Ni-W 1 O 3-x /C anode achieve a peak power density of 759 mW cm -2 and exhibits outstanding durability, retaining 94.9% of its initial voltage after 230.5 h of continuous operation, outperforming most of the Ni-based HOR catalysts reported previously.